…the Great Lakes were resuscitated after a century’s worth of industrial abuse only to be hit with an even more vexing environmental catastrophe.

Tragically for the Great Lakes, the Clean Water Act helped to lull most of the public into thinking that the lakes…were on their way to recovery throughout the 1970s, ’80s and ’90s. But the law—or more specifically ther agency charged with enforcing it—in fact did unfathomable damage to the lakes. It turned out that the federal regulators decided to exempt one industry’s form of “living pollution”—biologically contaminated watrer discharged from freighters.

This led to an explosion of invasive species, most notably Zebra and Quagga mussels that in less than 20 years became the lakes’ dominant species.

—Dan Egan, The Death & Life of the Great Lakes (2017).